well, it seems the mouse problem is not fixed.
I have the mouse just fine if I play just after installing the game and using the "Launch game" option.
But as soon as I leave the game, the mouse is gone.
It is very weird having the install the game every time I wish to play.
(I originally used an old version of the game, then installed the new version over it. When this still didn't work out, I deinstalled the game and then reinstalled it again. Still having a disappearing mouse.)